Copyright protects original expression in fixed form. “Original” means there must be some element of “authorship,” but the standard here is very low. A phone book is not sufficiently original, but my grocery list probably is. “Fixed” means that the expression must be available in a medium that can be perceived; unrecorded oral expression is not protected. Most importantly, “expression” means that copyright does not protect ideas, only the form in which those ideas are expressed. I am free to use ideas gained from another’s work in my own original expression without authorization.